1. Field of Invention
This invention relates generally to a lamp of the type in which a light bulb housing is supported at the end of an arm extending from a base, and more particularly to a lamp whose arm is extensible, and whose arm angle relative to the base is adjustable, whereby the lamp housing may be oriented, as desired, to illuminate an area of interest.
2. Status of Prior Art
A lamp whose bulb is at a fixed position relative to its base creates an unchanging illumination pattern. In those situations where the need exists to meet changing requirements for illumination, the conventional lamp is unsuited for this purpose.
For example, it is often necessary at a work bench to concentrate light on a given bench area and to then in the course of work shift the light beam onto another area to best view the object being worked on. Depending on the illumination requirements, proper illumination may be obtained by raising or lowering the light bulb housing and by changing the angle of the housing relative to the base. While a high-intensity bulb, such as a halogen bulb, is useful for close work, unless the bulb housing is properly oriented, adequate illumination will not be obtained.
Lamps are known having a light bulb housing whose position on a vertical post is adjustable to change the elevation of the housing relative to the lamp base. Also known are lamps in which the arm or post supporting the lamp housing is formed of telescoping elements, making it possible to adjust the height of the housing. In many lamps of these types, the housing is pivotally mounted on the post so that its angle is adjustable.
Also known are lamps in which the bulb housing is supported on a counterbalanced cantilever arm that is pivoted on a post. In another well-known type of lamp, the housing is supported on an articulated arm formed of interhinged and spring-biased sections, making it possible to adjust the elevation as well as the angle of the housing.
One problem common to all such known forms of lamps is the wiring for the bulb. In those instances where the arm is of fixed length and is hollow, the electrical two-wire line for the bulb may be housed within the arm. But in other cases, the line is external to the articulated arm or whatever other adjustable support means for the housing are provided. This exposed electrical line is unsightly and detracts from the appearance of the lamp. Also, the length of the line must correspond to the maximum length of the adjustable arm; hence when the arm is shortened to lower the bulb position, the line then bows out to create an unsightly loop.
Another drawback of many conventional adjustable lamps is that clamps, set screws and other expedients must be used to maintain the lamp at an adjusted position, and each time a change is made, it then becomes necessary to loosen and then tighten the clamps. In the case of an articulated arm whose sections are pivoted together, these pivots tend to loosen with repeated use and must be tightened to increase their resistance.
Another problem experienced with lamps having an articulated arm formed by sections which assume different angles with respect to each other when the lamp position is adjusted, is that the greater the angles, the more space is required to accommodate the sections. When a lamp of this type is placed in a confined space, it may not then be possible to adjust the lamp as desired.
Of particular prior art interest is the patent to Nicolosi, U.S. Pat. No. 3,369,117, which discloses a high-intensity lamp in which a telescoping element of the adjustable arm acts as a conductor to connect the bulb to a transformer.